1. Field of the Invention
This application relates to the field of vibration analysis and more particularly to performing vibration analysis for the purpose of device monitoring.
2. Description of Related Art
The transmission of power to rotors which propel helicopters and other shafts that propel devices within the aircraft induce vibrations in the supporting structure. The vibrations occur at frequencies that correspond to the shaft rotation rate, mesh rate, bearing passing frequency, and harmonics thereof. The vibration is associated with transmission error (TE). Increased levels of TE are associated with transmission failure. Similar types of vibrations are produced by transmissions in fixed installations as well.
Parts, such as those that may be included in a helicopter transmission, may be replaced in accordance with a predetermined maintenance and parts replacement schedule. These schedules provide for replacement of parts prior to failure. The replacement schedules may indicate replacement time intervals that are too aggressive resulting in needless replacement of working parts. This may result in incurring unnecessary costs as airplane parts are expensive. Additionally, new equipment may have installed faulty or defective parts that may fail prematurely.
Thus it may be desirable to provide for an efficient technique for detecting part and device degradation without unnecessarily replacing parts. It may be desirable that this technique also provide for problem determination and detection prior to failure.
In accordance with one aspect of the invention are a method executed in a computer system and computer program product for normalizing a set of at least one observed condition indicator. A plurality of conditional indicators and at least one associated factor are determined in accordance with previous data acquisitions. A mean and at least one model coefficient corresponding to said at least one associated factor are determined. The set of observed condition indicators is adjusted in accordance with model coefficients and said at least one associated factor producing a normalized set of condition indicators.